Have been using BirdieSyc since early 2014 and this has been a constant problem. Currently using 3.1.0.1
We use Birdie to fully sync between a desktop profile and an Android device.
Then the profile (unchanged and identical) is copied to a laptop. Takes a little over 3 minutes to copy a 5.25 GB profile.
When you then try to sync the laptop (with the unchanged and identical profile)to the same phone, Birdie thinks it has to rewrite everything again.
If that were an extra 5 minutes, no complaint, but this process takes almost two hours on each machine because the total number of deleted and rewritten items is 3598.https://s18.postimg.org/icdxhnzk9/Sync1.jpg
Birdie deletes every single contact and every single event and then writes them again to the very same android device even though the profiles are identical. It's a mystery to me what Birdie is "checking" during the 8-10 minutes when it is "preparing" to synchronize, because even with no changes to the profile, everything gets deleted and rewritten in any event.
A fix for this issue or a reasonable work-around would be appreciated.

And another issue with sync times is with events.
If you re-sync after a complete sync, on the same machine to the same android device, contacts complete in a few seconds, but events take half an hour.
This is with NO CHANGES to events.

I would need the full log archive to investigate on your problem.
While your Android device is connected (this is important to retrieve Android logs), could you build a log archive with BirdieSync menu "Help/Archive logs..." and then send BirdieSyncLog.zip to support(at)birdiesync.com ?

Could you also mention if you regularly backup and restore your Thunderbird profile with another software and if you synchronize your Thunderbird contacts and events with another software ?

More personally identifiable information in those logs than I am willing to share.

Seems that the basic issue is that BirdieSync feels the need to completely rebuild the Synchronization3.sdb file in the C:\Users\username\AppData\Roaming\BirdieSync folder even though both profiles are theoretically identical.

However, if after moving the Thunderbird profile from the desktop to the laptop, all of the files in the desktop's C:\Users\username\AppData\Roaming\BirdieSync folder are copied to the identical folder on the laptop, the two hour sync (delete and re-write) does not occur.

Could you also mention if you regularly backup and restore your Thunderbird profile with another software and if you synchronize your Thunderbird contacts and events with another software ?

Can you confirm that you also synchronize your Android device on your laptop with another BirdieSync server installed on your laptop ?
Is the synchronization of your address books and calendars configured in BirdieSync with Read/Write or Read Only permission ? If yes, on which source ? (Thunderbird or Android)
Do you reset the synchronization (combine or replace your contacts or events) when you switch from the desktop to the laptop or vice versa ?

Did you enable the search of duplicates in BirdieSync server configuration ? (BirdieSync menu "File/Search for duplicates") Or is it disabled ?
Do you only synchronize local calendars in Thunderbird or do you also synchronize remote calendars (in this case which type: ICS, calDAV, etc.)

Can you confirm that you also synchronize your Android device on your laptop with another BirdieSync server installed on your laptop ?

Yes. The desktop and laptop have their own separate installations of BirdieSync 3.1.0.1, and both synchronize with the same Android device(s).

Is the synchronization of your address books and calendars configured in BirdieSync with Read/Write or Read Only permission ?

Synchronization can only read the Thunderbird profile address book and calendar on both machines - the Tbird profile cannot be modified.
Synchronization on both machines can only write to the Android device(s) address book(s) and calendar(s).

Do you reset the synchronization (combine or replace your contacts or events) when you switch from the desktop to the laptop or vice versa ?

There is a single 'Master' Thunderbird profile - in the sense that all updates to Tbird address book and calendar are done to the 'Master' profile, and then that 'Master' profile is copied directly to the other Windows device. When I am close to the desktop, the 'Master' resides there, when I travel, that desktop profile is copied to the laptop and the Android devices sync with the laptop's Tbird profile. When I return, the laptop's Tbird profile is copied to the desktop. Theoretically, there is never a situation when the address book(s) and calendar(s) of the Android device(s) are synchronized with anything other that the 'Master' Tbird profile.

Did you enable the search of duplicates in BirdieSync server configuration ? (BirdieSync menu "File/Search for duplicates") Or is it disabled ?

My version does not display a Search for duplicates option, however 'Remove duplicates' is disabled.

Do you only synchronize local calendars in Thunderbird or do you also synchronize remote calendars (in this case which type: ICS, calDAV, etc.)

I only sync the local calendar in the Tbird profile with the Android devices.

If you installed BirdieSync on 2 different PCs and synchronize with these 2 different servers, it means that each server will have its own current state of the synchronization. These states are independent from each other. This means that if you synchronize on one PC with your Android device, and then transfer Thunderbird profile to the second PC, the second instance of BirdieSync server will not be aware that the Android device and Thunderbird are already identical, and will consider that both sides were modified since its last synchronization.

This is especially true if for some reason, at one time, you asked for the replacement of all your items on the Android device with Thunderbird ones. These could lead to a cycle of deletions and recreations, each time you switch to another PC, because of the Read Only permission on both PCs, which can revert changes made on the Android device. This cycle may possibly end if before synchronizing on the second PC, you reset its synchronization of the address book or calendar (set synchronization mode to Combine), after a global replacement on the first PC. But because of the Read Only permission, it's possible that some items are still synchronized at each switching of PC, if BirdieSync finds small differences in these items on the Android device and in Thunderbird.

The better workaround to this situation would be, as you already did, to copy BirdieSync roaming files, along with your Thunderbird profile to the new PC to use the same synchronization state on both PCs. It only works if Thunderbird profiles holds the same BirdieSync identifier (which is the case if the 2 profiles are a copy of each other).

Now some improvements may be made in the future to avoid unnecessary operations when items are found identical on both sides.